Thank you! I got the prm 02 working. I had to drop some solder on the two pads on the bottom of the board to enable OSD. Problem now is when my 3dr radio is plugged in to telemetry port, the apm shuts off. I know the radio is good. Works on another quad. Checked voltages, polarity, etc. Defective board maybe? Software issue? Can't find solution anywhere. Oh, no voltage reading from the prm 02. Oh well, getting closer. If I wanted easy I could have bought a Parrot.Heh Heh.Have a great day, or night wherever you are.

Damn! I like learning things the hard way. Wow, that's a long way from Chicago, Illinois. My European geography is terrible. Had to Google it. What an interesting country.Well, then have a great day! I will be following you around. Thanks again. :)

Uh oh, maybe using the Ic2 port for the prm 02 somehow screws up the telemetry port. Maybe you can't do both. I did not test the telemetry port before the mod. I will de-solder the jumpers and test the telemetry. If that works, I'm going with your schematic.

Great job! I've learned a lot here. Just one question. How did you connect the pwm-02 to the APM? I am not having any luck with getting it to work. I have tried connecting it to the IC2 socket as shown on Radiolink site. Checked power, RX TX and ground, still no